Note: Descriptions are shown in the official language in which they were submitted.
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, . , = ,
METHODS AND APPARATUS FOR LIMITING COMMUNICATION CAPABILITIES
IN MOBILE COMMUNICATION DEVICES
This application is a divisional application of application No. 2,658,110,
filed
November 9, 2004, which is a divisional of application No. 2,487,318, filed
November 9,
2004.
BACKGROUND
Field of the Invention
The present invention relates generally to mobile communication devices which
operate in wireless communication networks, and more particularly to methods
and
apparatus for limiting communication capabilities at the mobile device based
on
predetermined conditions detected at the mobile device.
Description of the Related Art
Modern-day mobile communication devices which operate in wireless
communication networks provide end users with the ability to place and receive
two-way
voice calls, send and receive text messages and e-mail messages, and send and
receive
other information such as Internet data. Such communication devices utilize a
radio
frequency (RF) transceiver for transmitting and receiving such information.
Unfortunately, adverse conditions (such as adverse temperature conditions) may
compromise the performance or utility of the mobile device. For example, when
a mobile
device is communicating information with use of its RF transceiver, the RF
transceiver
heats up and its temperature rises. If the temperature of the RF transceiver
is outside
certain specification parameters, the RF transceiver undesirably emits
spurious signals at
unacceptable levels. These spurious signals may be outside certain standards,
such as
those established by the Federal Communications Commission (FCC) or Industry
Canada, for example, and/or cause interference with other communications in
the
network. In addition, if the temperature of a rechargeable battery of the
mobile device is
outside certain specification parameters for too long, the battery may
experience
permanent damage and require replacement or could even explode.
Under such adverse conditions, the mobile station could power down its
circuitry
and inhibit all communications, but the end user would be left with no ability
to
communicate information. This would be undesirable in at least some
circumstances,
such as in emergency situations. What are needed are methods and apparatus
which
overcome the deficiencies of current practices.
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BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of present invention will now be described by way bf example with
reference to attached figures, wherein:
FIG. 1 is a block diagram which illustrates pertinent components of a mobile
communication device which communicates within a wireless communication
network;
FIG. 2 is a more detailed diagram of a preferred mobile communication device
of
FIG. 1;
FIG. 3 is a state diagram showing various communicating states of the mobile
communication device of FIGs. 1 and 2; and
FIG. 4 is a flowchart for describing a method of limiting communication
capabilities
in the mobile communication device of FIGs. 1 and 2.
DETAILED DESCRIPTION
FIG. 1 is a block diagram of a communication system 100 which includes a
mobile
station 102 which communicates through a wireless communication network 104.
Mobile
station 102 preferably includes a visual display 112, a keyboard 114, and
perhaps one or
more auxiliary user interfaces (UI) 116, each of which is coupled to a
controller 106.
Controller 106 is also coupled to radio frequency (RF) transceiver circuitry
108 and an
antenna 110.
Typically, controller 106 is embodied as a central processing unit (CPU) which
runs operating system software in a memory component (not shown). Controller
106 will
normally control overall operation of mobile station 102, whereas signal
processing
operations associated with communication functions are typically performed in
RF
transceiver circuitry 108. Controller 106 interfaces with device display 112
to display
received information, stored information, user inputs, and the like. Keyboard
114, which
may be a telephone type keypad or full alphanumeric keyboard, is normally
provided for
entering data for storage in mobile station 102, information for transmission
to network
104, a telephone number to place a telephone call, commands to be executed on
mobile
station 102, and possibly other or different user inputs.
Mobile station 102 sends communication signals to and receives communication
signals from network 104 over a wireless link via antenna 110. RF transceiver
circuitry
108 performs functions similar to those of a radio network (RN) 128, including
for
example modulation/demodulation and possibly encoding/decoding and
encryption/decryption. It is also contemplated that RF transceiver circuitry
108 may
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perform certain functions in addition to those performed by RN 128. It will be
apparent to
those skilled in art that RF transceiver circuitry 108 will be adapted to
particular wireless
network or networks in which mobile station 102 is intended to operate.
Mobile station 102 may consist of a single unit, such as a data communication
device, a cellular telephone, a multiple-function communication device with
data and
voice communication capabilities, a personal digital assistant (PDA) enabled
for wireless
communication, or a computer incorporating an internal modem. Alternatively,
mobile
station 102 may be a multiple-module unit comprising a plurality of separate
components,
including but in no way limited to a computer or other device connected to a
wireless
modem. In particular, for example, in the mobile station block diagram of FIG.
1, RF
transceiver circuitry 108 and antenna 110 may be implemented as a radio modem
unit
that may be inserted into a port on a laptop computer. In this case, the
laptop computer
would include display 112, keyboard 114, one or more auxiliary Uls 116, and
controller
106 embodied as the computer's CPU. It is also contemplated that a computer or
other
equipment not normally capable of wireless communication may be adapted to
connect to
and effectively assume control of RF transceiver circuitry 108 and antenna 110
of a
single-unit device such as one of those described above. Such a mobile station
102 may
have a more particular implementation as described later in relation to mobile
station 202
of FIG. 2.
Mobile station 102 includes a battery interface 122 for receiving one or more
rechargeable batteries 124 or a battery pack. Battery 124 provides electrical
power to
electrical circuitry in mobile station 102, and battery interface 122 provides
for a
mechanical and electrical connection for battery 124. Battery interface 122 is
coupled to
a regulator 126 which regulates power to the device. Mobile station 102 also
operates
using a memory module 120, such as a Subscriber Identity Module (SIM) or a
Removable
User Identity Module (R-UIM), which is connected to or inserted in mobile
station 102 at
an interface 118. As an alternative to a SIM or an R-UIM, mobile station 102
may operate
based on configuration data programmed by a service provider into a memory
module
within controller 106 which is a non-volatile memory.
Mobile station 102 also includes one or more temperature sensors and a battery
voltage sensor 154 which are used to control its operational states and
communication
capabilities (described later in detail in relation to FIGs. 3-4). In the
present embodiment,
two temperature sensors are included in mobile station 102. One temperature
sensor
150 is located adjacent RF transceiver 108 and, more specifically, adjacent to
a power
amplifier (PA) of RF transceiver 108. Temperature sensor 150 is coupled to
controller
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106 which continually monitors a temperature from temperature sensor 150.
Temperature sensor 150 may be, for example, a thermistor having a resistance
which
varies in accordance with temperature changes which are detected as voltage
changes at
controller 106. When mobile station 102 is communicating information with use
of RF
transceiver 108 (e.g. with its transmitter on), for example, RF transceiver
108 heats up
and its temperature rises. The ambient temperature also affects the operating
temperature of RF transceiver 108. If the temperature of RF transceiver 108 is
outside
certain specification parameters, spurious signals would be undesirably
emitted at
unacceptable levels. However, mobile station 102 operates to eliminate or
reduce the
possibility of such occurrences as will be described later below in relation
to FIGs. 3 and
4.
Note that, although only a single temperature sensor 150 is shown and
described
for RF transceiver 108, a temperature sensor may be utilized for each one of
multiple PAs
in mobile station 102 which correspond to multiple frequency bands within
which the
mobile station 102 may operate (e.g. cellular band, PCS band, etc.).
Another temperature sensor 152 may be located in battery or battery pack 124.
Temperature sensor 152 is coupled to controller 106 through battery interface
122.
Temperature sensor 152 may be, for example, a thermistor which fluctuates its
resistance
in accordance with changes in temperature to provide a change in voltage which
is
detected at controller 106. When mobile station 102 is communicating
information with
use of RF transceiver 108 (e.g. with its transmitter on), for example, battery
124 heats up
and its temperature rises. The ambient temperature also affects the
temperature of
battery 124. If the temperature of battery 124 is outside certain
specification parameters
for too long of a time period, battery 124 may experience permanent damage and
require
replacement or could even explode. However, mobile station 102 operates to
eliminate
or reduce the possibility of such occurrences as will be described later below
in relation to
FIGs. 3 and 4.
Battery voltage sensor 154 is also coupled to controller 106 through battery
interface 122. Battery voltage sensor 154 may be implemented using an analog-
to-digital
(A/D) converter, for example. Battery voltage sensor 154 is used to
continually measure
the voltage of battery 256, so that controller 106 may appropriately control
RF transceiver
108. In particular, when the battery voltage becomes low, mobile station 102
operates to
limit the use of RF transceiver 108 to extend the life of battery 124 as will
be described
later below.
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Mobile station 102 communicates in and through wireless communication network
104. In the embodiment of FIG. 1, wireless network 104 is a Third Generation
(3G)
supported network based on Code Division Multiple Access (CDMA) technologies.
In
particular, wireless network 104 is a cdma2000TM network which includes fixed
network
components coupled as shown in FIG. 1. Coma2000TM is a trademark of the
Telecommunications Industry Association (TIA). Wireless network 104 of the
cdma2000TM type includes a Radio Network (RN) 128, a Mobile Switching Center
(MSC)
130, a Signaling System 7 (SS7) network 140, a Home Location
Register/Authentication
Center (HLR/AC) 138, a Packet Data Serving Node (PDSN) 132, an IP network 134,
and
a Remote Authentication Dial-In User Service (RADIUS) server 136. SS7 network
140 is
communicatively coupled to a network 142 (such as a Public Switched Telephone
Network or PSTN), whereas IP network is communicatively coupled to a network
144
(such as the Internet).
During operation, mobile station 102 communicates with RN 128 which performs
functions such as call-setup, call processing, and mobility management. RN 128
includes
a plurality of base station transceiver systems that provide wireless network
coverage for
a particular coverage area commonly referred to as a"celP'. A given base
station
transceiver system of RN 128, such as the one shown in FIG. 1, transmits
communication
signals to and receives communication signals from mobile stations within its
cell. The
base station transceiver system normally performs such functions as modulation
and
possibly encoding and/or encryption of signals to be transmitted to the mobile
station in
accordance with particular, usually predetermined, communication protocols and
parameters, under control of its controller. The base station transceiver
system similarly
demodulates and possibly decodes and decrypts, if necessary, any communication
signals received from mobile station 102 within its cell. Communication
protocols and
parameters may vary between different networks. For example, one network may
employ
a different modulation scheme and operate at different frequencies than other
networks.
The underlying services may also differ based on its particular protocol
revision.
The wireless link shown in communication system 100 of FIG. 1 represents one
or
more different channels, typically different radio frequency (RF) channels,
and associated
protocols used between wireless network 104 and mobile station 102. An RF
channel is
a limited resource that must be conserved, typically due to limits in overall
bandwidth and
a limited battery power of mobile station 102. Those skilled in art will
appreciate that a
wireless network in actual practice may include hundreds of cells depending
upon desired
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overall expanse of network coverage. All pertinent components may be connected
by
multiple switches and routers (not shown), controlled by multiple network
controllers.
For all mobile station's 102 registered with a network operator, permanent
data
(such as mobile station 102 user's profile) as well as temporary data (such as
mobile
station's 102 current location) are stored in a HLR/AC 138. In case of a voice
call to
mobile station 102, HLR/AC 138 is queried to determine the current location of
mobile
station 102. A Visitor Location Register (VLR) of MSC 130 is responsible for a
group of
location areas and stores the data of those mobile stations that are currently
in its area of
responsibility. This includes parts of the permanent mobile station data that
have been
transmitted from HLR/AC 138 to the VLR for faster access. However, the VLR of
MSC
130 may also assign and store local data, such as temporary identifications.
Mobile
station 102 is also authenticated on system access by HLR/AC 138. In order to
provide
packet data services to mobile station 102 in a cdma2000TM based network, RN
128
communicates with PDSN 132. PDSN 132 provides access to the Internet 144 (or
intranets, Wireless Application Protocol (WAP) servers, etc.) through IP
network 134.
PDSN 132 also provides foreign agent (FA) functionality in mobile IP networks
as well as
packet transport for virtual private networking. PDSN 132 has a range of IP
addresses
and performs IP address management, session maintenance, and optional caching.
RADIUS server 136 is responsible for performing functions related to
authentication,
authorization, and accounting (AAA) of packet data services, and may be
referred to as
an AAA server.
Those skilled in art will appreciate that wireless network 104 may be
connected to
other systems, possibly including other networks, not explicitly shown in FIG.
1. A
network will normally be transmitting at very least some sort of paging and
system
information on an ongoing basis, even if there is no actual packet data
exchanged.
Although the network consists of many parts, these parts all work together to
result in
certain behaviours at the wireless link. We use a cdma2000TM network as an
example for
the description, but these techniques in the present application are not
limited to the use
of cdma2000TM.
FIG. 2 is a detailed block diagram of a preferred mobile station 202. Mobile
station 202 is preferably a two-way communication device having at least voice
and
advanced data communication capabilities, including the capability to
communicate with
other computer systems. Depending on the functionality provided by mobile
station 202,
it may be referred to as a data messaging device, a two-way pager, a cellular
telephone
with data messaging capabilities, a wireless Internet appliance, or a data
communication
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device (with or without telephony capabilities). Mobile station 202 may
communicate with
any one of a plurality of base station transceiver systems 200 within its
geographic
coverage area.
Mobile station 202 will normally incorporate a communication subsystem 211,
which includes a receiver 212, a transmitter 214, and associated components,
such as
one or more (preferably embedded or internal) antenna elements 216 and 218,
local
oscillators (LOs) 213, and a processing module such as a digital signal
processor (DSP)
220. Communication subsystem 211 is analogous to RF transceiver circuitry 108
and
antenna 110 shown in FIG. 1. As will be apparent to those skilled in field of
communications, particular design of communication subsystem 211 depends on
the
communication network in which mobile station 202 is intended to operate.
Mobile station 202 may send and receive communication signals over the network
after required network registration or activation procedures have been
completed.
Signals received by antenna 216 through the network are input to receiver 212,
which
may perform such common receiver functions as signal amplification, frequency
down
conversion, filtering, channel selection, and like, and in example shown in
FIG. 2, analog-
to-digital (A/D) conversion. A/D conversion of a received signal allows more
complex
communication functions such as demodulation and decoding to be performed in
DSP
220. In a similar manner, signals to be transmitted are processed, including
modulation
and encoding, for example, by DSP 220. These DSP-processed signals are input
to
transmitter 214 for digital-to-analog (D/A) conversion, frequency up
conversion, filtering,
amplification and transmission over communication network via antenna 218. DSP
220
not only processes communication signals, but also provides for receiver and
transmitter
control. For example, the gains applied to communication signals in receiver
212 and
transmitter 214 may be adaptively controlled through automatic gain control
algorithms
implemented in DSP 220.
Network access is associated with a subscriber or user of mobile station 202,
and
therefore mobile station 202 requires a memory module 262, such as a
Subscriber
Identity Module or "SIM" card or a Removable User Identity Module (R-UIM), to
be
inserted in or connected to an interface 264 of mobile station 202 in order to
operate in
the network. Alternatively, flash memory 224 may be a non-volatile memory
which is
programmed with configuration data by a service provider so that mobile
station 202 may
operate in the network. Since mobile station 202 is a mobile battery-powered
device, it
also includes a battery interface 254 for receiving one or more rechargeable
batteries
256. Such a battery 256 provides electrical power to most if not all
electrical circuitry in
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mobile station 202, and battery interface 254 provides for a mechanical and
electrical
connection for it. The battery interface 254 is coupled to a regulator (not
shown in FIG. 2)
which provides power V+ to all of the circuitry.
Mobile station 202 includes a microprocessor 238 (which is one implementation
of
controller 106 of FIG. 1) which controls overall operation of mobile station
202. This
control includes network selection techniques of the present application.
Communication
functions, including at least data and voice communications, are performed
through
communication subsystem 211. Microprocessor 238 also interacts with additional
device
subsystems such as a display 222, a flash memory 224, a random access memory
(RAM) 226, auxiliary input/output (I/O) subsystems 228, an external
communication port
230, a keyboard 232, a speaker 234, a microphone 236, a short-range
communications
subsystem 240, and any other device subsystems generally designated at 242.
Some of
the subsystems shown in FIG. 2 perform communication-related functions,
whereas other
subsystems may provide "resident" or on-device functions. Notably, some
subsystems,
such as keyboard 232 and display 222, for example, may be used for both
communication-related functions, such as entering a text message for
transmission over
a communication network, and device-resident functions such as a calculator or
task list.
Operating system software used by microprocessor 238 is preferably stored in a
persistent store such as flash memory 224, which may alternatively be a read-
only
memory (ROM) or similar storage element (not shown). Those skilled in the art
will
appreciate that the operating system, specific device applications, or parts
thereof, may
be temporarily loaded into a volatile store such as RAM 226.
Microprocessor 238, in addition to its operating system functions, preferably
enables execution of software applications on mobile station 202. A
predetermined set of
applications which control basic device operations, including at least data
and voice
communication applications, will normally be installed on mobile station 202
during its
manufacture. A preferred application that may be loaded onto mobile station
202 may be
a personal information manager (PIM) application having the ability to
organize and
manage data items relating to user such as, but not limited to, e-mail,
calendar events,
voice mails, appointments, and task items. Naturally, one or more memory
stores are
available on mobile station 202 and SIM 262 to facilitate storage of PIM data
items and
other information.
The PIM application preferably has the ability to send and receive data items
via
the wireless network. In a preferred embodiment, PIM data items are seamlessly
integrated, synchronized, and updated via the wireless network, with the
mobile station
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user's corresponding data items stored and/or associated with a host computer
system
thereby creating a mirrored host computer on mobile station 202 with respect
to such
items. This is especially advantageous where the host computer system is the
mobile
station user's office computer system. Additional applications may also be
loaded onto
mobile station 202 through network, an auxiliary I/O subsystem 228,
communication port
230, short-range communications subsystem 240, or any other suitable subsystem
242,
and installed by a user in RAM 226 or preferably a non-volatile store (not
shown) for
execution by microprocessor 238. Such flexibility in application installation
increases the
functionality of mobile station 202 and may provide enhanced on-device
functions,
communication-related functions, or both. For example, secure communication
applications may enable electronic commerce functions and other such financial
transactions to be performed using mobile station 202.
In a data communication mode, a received signal such as a text message, an e-
mail message, or web page download will be processed by communication
subsystem
211 and input to microprocessor 238. Microprocessor 238 will preferably
further process
the signal for output to display 222 or alternatively to auxiliary I/O device
228. A user of
mobile station 202 may also compose data items, such as e-mail messages, for
example,
using keyboard 232 in conjunction with display 222 and possibly auxiliary I/O
device 228.
Keyboard 232 is preferably a complete alphanumeric keyboard and/or telephone-
type
keypad. These composed items may be transmitted over a communication network
through communication subsystem 211.
For voice communications, the overall operation of mobile station 202 is
substantially similar, except that the received signals would be output to
speaker 234 and
signals for transmission would be generated by microphone 236. Alternative
voice or
audio I/O subsystems, such as a voice message recording subsystem, may also be
implemented on mobile station 202. Although voice or audio signal output is
preferably
accomplished primarily through speaker 234, display 222 may also be used to
provide an
indication of the identity of a calling party, duration of a voice call, or
other voice call
related information, as some examples.
Communication port 230 in FIG. 2 is normally implemented in a personal digital
assistant (PDA)-type communication device for which synchronization with a
user's
desktop or laptop computer is a desirable, albeit optional, component.
Examples of such
a port include an RS-232 port and a Universal Serial Bus (USB). Communication
port
230 enables a user to set preferences through an external device or software
application
and extends the capabilities of mobile station 202 by providing for
information or software
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downloads to mobile station 202 other than through a wireless communication
network.
The alternate download path may, for example, be used to load an encryption
key onto
mobile station 202 through a direct and thus reliable and trusted connection
to thereby
provide secure device communication.
Short-range communications subsystem 240 of FIG. 2 is an additional optional
component which provides for communication between mobile station 202 and
different
systems or devices, which need not necessarily be similar devices. For
example,
subsystem 240 may include an IrDATM communication module or a BluetoothTM
communication module to provide for communication with similarly-enabled
systems and
devices. IrDATM and BluetoothTM are trademarks of Infrared Data Association
and
Bluetooth SIG Inc., respectively. A PDA-type communication device may also use
IrDA
or Bluetooth technology for synchronization with a user's desktop or laptop
computer.
Mobile station 202 also includes one or more temperature sensors and a battery
voltage sensor 290 which are used to control its operational states and
communication
capabilities (described later in detail in relation to FIGs. 3-4). In the
present embodiment,
two temperature sensors are included in mobile station 202. One temperature
sensor
280 is located adjacent communication subsystem 211 and, more specifically,
adjacent to
a power amplifier (PA) of communication subsystem 211, for example.
Temperature
sensor 280 is coupled to microprocessor 238, which continually monitors a
temperature
from temperature sensor 280. Temperature sensor 280 may be, for example, a
thermistor having a resistance which varies in accordance with changes in
temperature to
provide a change in voltage detected at microprocessor 238. When mobile
station 202 is
communicating information with use of communication subsystem 211 (e.g. with
its
transmitter 214 on), for example, communication subsystem 211 heats up and its
temperature rises. The ambient temperature also affects the temperature of
components
in communication subsystem 211. If the temperature of communication subsystem
211 is
outside certain specification parameters, spurious signals would be
undesirably emitted
by transmitter 214 at unacceptable levels. However, mobile station 202
operates to
eliminate or reduce the possibility of such occurrences as will be described
later below in
relation to FIGs. 3 and 4.
Note that, although only a single temperature sensor 280 is shown and
described
for communication subsystem 211, a temperature sensor may be utilized for each
one of
multiple PAs in mobile station 202 which correspond to multiple frequency
bands within
which the mobile station 202 may operate (e.g. cellular band, PCS band, etc.).
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Another temperature sensor 282 is located in battery or battery pack 256.
Temperature sensor 282 is coupled to microprocessor 238 through battery
interface 254.
Temperature sensor 282 may be, for example, a thermistor which fluctuates its
resistance
in accordance with changes in temperature to provide a change in voltage
detected at
microprocessor 238. When mobile station 202 is communicating information with
use of
communication subsystem 211 (e.g. with its transmitter 214 on), for example,
battery 256
heats up and its temperature rises. The ambient temperature also affects the
temperature of battery 256. If the temperature of battery 256 is outside
certain
specification parameters for too long of a time period, battery 256 may
experience
permanent damage and require replacement or could even explode. However,
mobile
station 202 operates to eliminate or reduce the possibility of such
occurrences as will be
described later below in relation to FIGs. 3 and 4.
Battery voltage sensor 290 is also coupled to microprocessor 238 through
battery
interface 254. Battery voltage sensor 290 may be implemented using an analog-
to-digital
(A/D) converter, for example. Battery voltage sensor 290 is used to
continually measure
the voltage of battery 256, so that microprocessor 238 may appropriately
control
communication subsystem 211. In particular, when the battery voltage becomes
low,
mobile station 202 operates to limit the use of communication subsystem 211 to
extend
the life of battery 256 as will be described later below.
FIG. 3 is a state diagram 300 which illustrates various operating states of a
mobile
communication device such as the mobile station shown and described in
relation to
FIGs. 1 and 2. More particularly, state diagram 300 illustrates various
communication
states which are responsive to different operating conditions of the mobile
station. In the
present embodiment of FIG. 3, the different communication states of the mobile
station
are responsive to different temperature conditions of the mobile station. The
changes in
communication states, however, could be responsive to other changing operating
conditions of the mobile station, such as low battery conditions or automatic
location-
based power down conditions (e.g. automatic airplane power down).
As shown in state diagram 300, the communication states of the mobile station
include a full communication state 302, a limited communication state 304, an
emergency-only text communication state 306, and an off state 308. In general,
the
mobile station continually monitors a reading from a sensor and selects one of
the
communication states 302, 304, 306, and 308 based on the reading. In
particular in FIG.
3, the mobile station monitors an operating temperature T based on a reading
from a
temperature sensor and selects one of the communication states 302, 304, 306,
and 308
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based on temperature. Several predetermined temperature thresholds are known
by and
stored in memory of the mobile station. In this exemplary embodiment, six (6)
different
temperature thresholds T1, T2, T3, T4, T5, and T6 are known by and stored in
the mobile
station, where T1 < T2 < T3 < T4 < T5 < T6. These six different temperature
thresholds
are associated with different operating temperature ranges which may include a
normal
operating temperature range T3 - T4; one or more poor operating temperature
ranges T2
- T3 and T4 - T5 (lower and upper, respectively); one or more very poor
operating
temperature ranges T1 - T2 and T5 - T6 (lower and upper, respectively); and
one or
more extremely poor operating temperature ranges less than T1 or greater than
T6.
Preferably, the mobile station selects one of the communication states 302,
304,
306, and 308 based on readings from more than one sensor. For example, the
mobile
station may select one of the communication states based on both the
temperature of the
RF PA and the temperature of the battery. As another example, the mobile
station may
select one of the communication states based on both the temperature of the RF
PA and
the battery voltage of the battery. Using this type of approach, each sensor
has a
corresponding set of predetermined thresholds which are stored in memory of
the mobile
station. Accordingly, a communication state of the mobile station is
determined and
selected based on readings and decisions from all of relevant sensors. For
example, the
mobile station may select the most limiting communication state associated
with any one
of the sensors as the current communication state.
For clarity, state diagram 300 of FIG. 3 will be described where a single
operating
temperature (which may be viewed as a composite reading from all sensors)
drives the
selection of a communication state. Under normal operating circumstances, the
mobile
station identifies the operating temperature T to be within a predetermined
temperature
range of T3 <_ T_ T4. T3 may be about -10 C and T4 may be about 60 C, for
example.
In this case, the mobile station will operate in full communication state 302.
In full
communication state 302, the mobile station allows its full communication
capabilities for
the end user. The mobile station permits two-way voice calls and data packet
communication sessions (e.g. e-mail message and Internet data communications).
The
wireless transceiver of the mobile station is kept operational, although the
transmitter and
receiver may be powered down intermittently in sleep modes when necessary to
conserve power as is conventional. The coding and modulation methods utilized
by the
wireless transceiver are not limited in any way in state 302. Preferably, a
visual indication
of this communication state is provided in the visual display of the mobile
station (e.g.
"FULL").
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In poor temperature conditions, the mobile station identifies the operating
temperature T to be within one of the poor operating temperature ranges, where
T2 s T <
T3 or T4 < T s T5. T2 may be about -20 C and T5 may be about 80 C, for
example. If
the operating temperature T is poor, spurious signals may be undesirably
emitted by the
transmitter at unacceptable levels when transmitting at the allowed maximum
transmit
power level in normal operating circumstances. Also, the battery may
experience
permanent damage and require replacement. Thus, if T2 s T < T3 or T4 < T s T5,
the
mobile station controls itself to operate in limited communication state 304.
In limited
communication state 304, the mobile station allows only limited communication
capabilities for the end user. The transmitter is normally powered off while
the receiver is
kept operational (albeit powered down intermittently in sleep modes to
conserve power as
is conventional). Alternatively, the transmitter and receiver are both powered
off. In
limited communication state 304, the mobile station does not permit any non-
emergency
communications such as non-emergency voice calls, non-emergency data service
(e.g.
communicating any normal e-mail message, Internet browsing, etc.), and over-
the-air
service provisioning.
In limited communication state 304, however, the mobile station does permit
the
placement of emergency two-way voice calls (e.g. 911 voice call) and permits
any
emergency data packet communication (e.g. emergency message or Internet data
communication). If an emergency communication request is received at the user
interface, the transmitter (and receiver where applicable) is powered on and
the
maximum transmit power is limited to a lower power level to reduce the
likelihood of
unacceptable spurious emissions. Also, the coding and modulation methods of
the
wireless transceiver may be limited for the same reasons. Preferably, after a
mobile-
initiated emergency communication, the mobile station invokes an emergency
callback
period during which mobile station enables and allows network-initiated
position location
services as well as incoming voice calls. Typically, a mobile station enters
an emergency
callback period lasting for five (5) minutes after an emergency call is
terminated. This
allows a Public Safety Answer Point (PSAP) the ability to call back and/or
locate the user
with use of technology such as Assisted Global Positioning System (A-GPS).
Preferably,
a visual indication of this communication state is provided in the visual
display of the
mobile station (e.g. "LIMITED" or "EMERGENCY ONLY").
Under more adverse temperature conditions, the mobile station identifies the
operating temperature T to be within one of the very poor operating
temperature ranges,
where T1 <_ T < T2 or T5 < T_ T6. T1 may be about -25 C and T6 may be about
100 C,
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CA 02697574 2010-03-26
for example. If the operating temperature T is at such a level, spurious
signals may be
undesirably emitted by the transmitter at unacceptable levels when
transmitting at the
allowed maximum transmit power level in normal operating circumstances. Also,
the
battery may experience permanent damage and require replacement. Furthermore,
the
receiver performance may be degraded. Thus, if T1 5 T < T2 or T5 < T<_ T6, the
mobile
station controls itself to operate in emergency-only text communication state
306. In
emergency-only text communication state 306, the transmitter and the receiver
are kept
powered down (i.e. completely powered off, not merely in a sleep mode of
operation).
The mobile station does not permit any services including non-emergency or
emergency
(e.g. 911) two-way voice calls, or non-emergency data packet transmissions for
end-user
communication (e.g. ordinary e-mail message and Internet data communications),
and
over-the-air service provisioning. The mobile station also does not permit the
reception of
ordinary data packet communications (e.g. ordinary e-mail messages). In
emergency-
only text communication state 306, the mobile station only permits a mobile-
initiated
communication of text-based emergency messages. Preferably, a visual
indication of this
communication state may be provided in the visual display of the mobile
station (e.g.
"EMERGENCY ONLY TEXT"), assuming that the visual display can operate under
such
conditions.
These emergency text messages may be in the form of a short message service
(SMS) message and/or an e-mail message, for example, which are communicated to
some form of a Public-Safety Answering Point (PSAP) supporting messages.
Preferably,
the text-based emergency message is a predefined, prestored emergency text
message
in the mobile station (e.g. "EMERGENCY - PLEASE HELP"). In general, the
sending of
the emergency text message is the only time that the transceiver is powered on
in state
306. The maximum transmit power is preferably limited at an even lower level
to reduce
the likelihood that no unacceptable spurious emissions exist. Also preferably,
the
emergency message is transmitted at a low data rate which requests a lower
transmit
power to achieve a given reliability of communication. Further, the coding and
modulation
methods of the wireless transceiver may be limited if necessary. The
information may be
sent over a control channel (e.g. an access channel) which eliminates the need
of setting
up a traffic channel. For example, the emergency text message may be in the
form of an
emergency SMS message transmitted over an access channel. The emergency
message may or may not be accompanied by user-identifying information and/or
location
information (e.g. pilot phase information). Preferably, such information is
included in the
emergency message. An audible indication may be provided at the user interface
to
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CA 02697574 2010-03-26
confirm that the emergency text message has been successfully transmitted
and/or
received (especially important where the visual display of the mobile station
may not be
operable under such conditions).
Under even more adverse operating conditions, the mobile station identifies
the
operating temperature T to be below temperature T1 or above temperature T6. If
the
operating temperature T is at such a level, spurious signals may be
undesirably emitted
by the transmitter at unacceptable levels or the battery may experience
permanent
damage and require replacement or could even explode. In this case, the mobile
station
controls itself to power down to the off state 308. In off state 308, the
mobile station is
completely shut down and no communication capabilities are provided for the
end user.
Not even emergency communications can be provided by the mobile station in off
state
308.
Thus, when a communication request for communicating information is received
through a user interface (e.g. keypad, keyboard, or touch screen display) of
the mobile
station, the mobile station will inhibit or allow the communication request
depending on
which communication state it is operating in. In the limited communication
state, for
example, the mobile station will inhibit a non-emergency communication but
allow an
emergency communication.
FIG. 4 is a flowchart which describes a method of limiting communication
capabilities in a mobile communication device such as the mobile station
described in
relation to FIGs. 1 and 2. The communication states and
temperatures/temperature
ranges correspond to those described in relation to state diagram 300 of FIG.
3. A
computer program product may include computer instructions stored on a
computer
storage medium (memory of the mobile station, a floppy disk or CD-ROM) which
are
written in accordance with the described logic.
Beginning at a start block 402 of FIG. 4, the mobile station detects whether
its
operating temperature T is within temperature range T3 - T4 (step 404). If so,
the mobile
station operates in its full communication state (step 406). If the operating
temperature T
is not within temperature range T3 - T4, the mobile station detects whether
the operating
temperature T is within temperature range T2 - T3 or T4 - T5 (step 408). If
so, the
mobile station operates in its limited communication state (step 410). If the
operating
temperature T is not within temperature range T2 - T3 or T4 - T5, the mobile
station
detects whether its operating temperature T is within temperature range T1 -
T2 or T5 -
T6 (step 412). If so, the mobile station operates in its emergency-only
communication
state (step 414). If the operating temperature T is not within T1 - T2 or T5 -
T6, the
CA 02697574 2010-03-26
mobile station detects whether its operating temperature T is less than T1 or
greater than
T6 (step 416). If so, the mobile station powers itself down completely (step
418). The
mobile station will remain powered down from step 418 until the end user
powers it back
up and the adverse condition is gone. Upon power up, the mobile station starts
again at
start block 402 and may operate to follow the previous decision to obtain the
device state.
For example, if the mobile station is determined to be in OFF state again, the
mobile
station powers itself off after an audible or visual indication to the user;
if the adverse
condition is gone, however, the mobile station will remain in a different
state
corresponding to current conditions.
Although FIGs. 3 and 4 are primarily directed to limiting communication
capabilities based on temperature, the techniques apply to limiting
communication
capabilities based on low battery voltage in the same way (or limiting
communication
capabilities based on the combined use of temperature(s) and low battery
voltage).
Final Comments. Methods and apparatus for limiting communication capabilities
in mobile communication devices have been described. In one illustrative
example, a
predetermined condition such as an unsatisfactory temperature or a low battery
voltage is
detected at the mobile communication device. At this time, a communication
request for
communicating information through a wireless communication network is received
through a user interface. If the communication request is for a non-emergency
communication, the non-emergency communication is inhibited during the
existence of
the predetermined condition. If the communication request is for an emergency
communication, however, the emergency communication is allowed despite the
existence
of the predetermined condition. The emergency communication may be a"911"
voice call
or an emergency message. The maximum allowed transmit power may be limited to
a
certain level to reduce the likelihood that unacceptable spurious emissions
exist. The
coding and modulation methods may also be limited to a subset of that which
the mobile
station would otherwise support.
The above-described embodiments of the present application are intended to be
examples only. Those of skill in the art may effect alterations, modifications
and
variations to the particular embodiments without departing from the scope of
the
application. For example, instead of using temperature-based conditions, low
battery
conditions or automatic location-based power down conditions (e.g. automatic
airplane
power down) may be utilized. The invention described herein in the recited
claims
intends to cover and embrace all suitable changes in technology.
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